grub2/0151-http-Prepend-prefix-when-the-HTTP-path-is-relative-a.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Tue, 2 Jun 2020 13:25:01 +0200
Subject: [PATCH] http: Prepend prefix when the HTTP path is relative as done
 in efi/http

There are two different HTTP drivers that can be used when requesting an
HTTP resource: the efi/http that uses the EFI_HTTP_PROTOCOL and the http
that uses GRUB's HTTP and TCP/IP implementation.

The efi/http driver appends a prefix that is defined in the variable
http_path, but the http driver doesn't.

So using this driver and attempting to fetch a resource using a relative
path fails.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---
 grub-core/net/http.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/grub-core/net/http.c b/grub-core/net/http.c
index b52b558d631..7f878b56157 100644
--- a/grub-core/net/http.c
+++ b/grub-core/net/http.c
@@ -501,13 +501,20 @@ http_open (struct grub_file *file, const char *filename)
 {
   grub_err_t err;
   struct http_data *data;
+  const char *http_path;
 
   data = grub_zalloc (sizeof (*data));
   if (!data)
     return grub_errno;
   file->size = GRUB_FILE_SIZE_UNKNOWN;
 
-  data->filename = grub_strdup (filename);
+  /* If path is relative, prepend http_path */
+  http_path = grub_env_get ("http_path");
+  if (http_path && filename[0] != '/')
+    data->filename = grub_xasprintf ("%s/%s", http_path, filename);
+  else
+    data->filename = grub_strdup (filename);
+
   if (!data->filename)
     {
       grub_free (data);